基于多元统计方法的长江口及邻近海域表层沉积物中重金属的时空分布特征

Study on the spatial and temporal distribution of the heavy metals in the surface sediments based on multivariate statistical technique from the Changjiang Estuary and its adjacent areas

应用聚类分析(cluster analysis,CA)、判别分析(discriminant analysis,DA)等多元统计学方法对2005—2009年长江口及邻近海域表层沉积物中重金属的时空分布特征进行分析,以识别沉积物中重金属指标的时间与空间差异性.时间聚类分析结果将沉积物中重金属在时间尺度上划分为2006年,2005年和2007—2009年两组,判别分析正确率为80%,表征时间差异性的显著性重金属指标为Zn、Hg.空间聚类分析结果将沉积物中重金属在空间尺度上划分为近岸区,长江河口锋和羽状锋区之间两个海域,判别分析正确率为90%,表征空间差异性的显著性重金属指标为Zn、Hg.

The multivariate statistical techniques such as cluster analysis（CA） and discrminant analysis（DA） were applied to study the temporal and spatial variations of the heavy metals in the surface sediments based on the surveys during 2005 to 2009.The spatial and temporal differences of the heavy metals in the surface sediment were also identified.According to the temporal analysis results,the heavy metals in sediments were classified into two periods 2006,2005 and 2007—2009）,the DA for accuracy was 80%,and the temporally significant parameters were Zn and Hg.According to the spatial analysis results,the heavy metals in sediments were classified into two areas（inshore zone,zone between estuarine front and plume area）,the DA for accuracy is 90%,and the spatially significant parameters were Zn and Hg.